It is impolite to eat food from another diner’s plate. If you would like to sample or share food from another diner’s plate, hand your fork to the other person who should place the food on the fork and hand it back to you, place the food on the edge of your plate, or place it on your bread plate. Do not reach over and take the food off the other person’s plate. Worst yet, do not allow the other person to lean over and mouth feed you.
Many times it is decided that a meal will be shared before ordering. If this is the case, inform your server you will be sharing your meal. The server should then bring it to the table on two individual plates.